Synthetic resins



Patented Jan. 13, 1953 SYNTHETIC REsINs.

George L. Doelling, St. Louis, and Kenneth H Adams; Fenton, Mo., assignors to Mississippi Valley- Research' Laboratories, Inc., St, Louis, Mo'., acorporati'on of Missouri No. Drawing. Application April 30, 19.4.9. Serial No. 90,762

I3. Claims. I

This invention relates to synthetic resins and more particularly to thermosetting synthetic resins.

Briefly the invention comprises synthetic thermosetting resins prepared by reacting; certain ether resins with phenol-formaldehyde resin. compositions and the processes; of preparing said synthetic: resins.

Among the, objects of this invention are the provision. of improved; synthetic resins which can be used in molding, laminating and in surface coatings; the provision of synthetic resins which are heat-hardened yet flexible; the provision of synthetic resins of thetype indicated which may be formed in situ without damaging relatively delicate fibers; the provision of synthetic resins made from preliminary stage resins which can be applied to the material to be treated and the final thermoset resin formed place by heating; and, the provision ofsynthetic-resinsor the type indicated which heat-harden to form hard, smooth, non-tacky and flexible films. Other features will be in part apparent and in part.

pointed out hereinafter.

The invention accordingly comprises the ingredients. and combinations. of. ingredients, the proportions thereof, stepsand. sequence of steps. and features of composition and. manipulation. which will be exemplified in the. products and methods hereinafter described-.- and. the scope of the application of which will be indicatedthe following claims.

The usual. phenol-aldehyde type. thermosetting resins possess. several characteristics" which rander them unsuitable for. many purposes where they could otherwise; be beneficially employed. Among some of these disadvantages are. their inherent brittleness and low impact resistance. The thermosetting resinsof. the present invention, however retain the. desirable. properties. of the. ordinary phenol-aldehyde type resins: and, moreover, are quite flexible. and have. a-hig h de- 'gree. of. resistance to impact. I

In accordancewith the. present invention novel thermosetting resins are .obtainedby the. reaction atv elevated temperatures of an. ether-type. resin and a heat-hardenable. .phenolraldehyde composition. The term heat-hardenable phenolformaldehyde composition-is. used to designate a phenol-formaldehyde resin composition which can be hardened into aha-rd-, thermoset, insoluble resin simply by theapplicaticn of heat. Such a heat-hardenable resin composition may comprise a phenol-formaldehyde resin witha high ratio of formaldehyde tophenol which is itself heat hardenable, such as acasting resin, or it may comprise an A-stage orfirst-stage; soluble,

phenol-formaldehyde resin plus addititmal form aldehyde, or an aldehyde producing substance;

and a catalystv intermixed therewith. Examples of suitable substances that: will. yield formaldehyde under certainconditions. of: heating. and processing include hexamethylenea tetramine. and paraaformaldehyde. Itis; to be understood that the phenol-formaldehyde. resin. used. may include other resins such asthose formed from formaldehyde and meta-cresol, or metarxylenol and mixtures of phenol and cresols and xylenols.

A number of substances may be utilized asoatalysts; to facilitate hardening. under heat: of the resin composition, for example, ethylenediamine, other aliphatic amines, aliphatic amino-alco: hols, and alkali oralkali'ne. earth metal hydroxides, or other alkaline catalysts. While it is preferred that analkaline catalyst; be. used, in some instances an acid such as; oxalic,.monochloracetic, boric. or phosphoric acid or some other acid in small quantitiesmay be used.. In general, however, acid catalysts. tend. to deteriorate or corrode. fabrics, fillers: and. metals with which they come: in contact.

The: ether resin employed in; the:- present. invention is madeiby reacting. in. the, presence. of an alkali and. at elevatedtemperatures certain dihydric phenols having: the. following: formula:

in which R is a hydrogen, a lower alkyl or a lower. acyl group, with a dihalide of a polyethylene lycol. ha ine h fol ow ng mu a):

in which n is an integer not less than three and not greater than thirty and X is selected from the group consisting of chlorine and bromine. The molar'ratio of the dihydric phenols to the po ye y dihal de i e erab y p oximately 1:1.

Not all dihydric phenols can be used to produce satisfactory ether resins according to this invention. Suitable compounds are resorcinol', orcinol', resa'cet'ophenone. and the loweralkyl' derivatives? of resorcino'l.

Suitable dihali'des' include the dichloride of tetraethylene giycol', t e dibromide of tetraethylene" g y o h iQh Q id h xa hr jene' glycol; h dichloride t nona t len yco t e dichloride of a polyethylene glycol having amolecular weight of 600; and the. dichloride of a polyethylene ycol; ha a mole ular wei ht of 1.000". In each case thesedichlorides are the compoundsformed by replacing" each of the two OH groups of apolyethylene glycol by halogen. The:- dichlorides; of polyethylene glycols lower than tetra. aret not; suitable-for this purposesince give the desired properties in the final product.

Structural analysis indicates that the resorcinol-ether type resin has a formula. approximately as follows:

where n is an integer not less than four and not more than thirty, m is an integer from approximately two to approximately ten, X is selected from the group consisting of chlorine and bromine and R represents hydrogen,'a lower alkyl or a lower acyl, group. However, notwithstanding the accuracy of the above structural representation, the reaction product of the certain dihydric phenols referred to above and the polyethylene glycol dihalides serves as one of the two resin components which are reacted together to form the flexible thermosetting resins of the present invention. This resorcinol-ether resin has the surprising and valuable property of acting as a built-in plasticizer for the final resin resulting from the reaction of the ether-type and the heat-hardenable phenol-aldehyde resin compositions.

The range of the ratio of the ether resin to the phenol-aldehyde type resin may be varied between approximately 1:9 to 9:1. However, an approximately equal ratio by weight of the component resins is preferably employed.

The synthetic resin of our invention can be coated on steel, cloth or wood or other substance as a surface coating which is very resistant to water, solvents, etc. It can also be used together with asbestos, cotton flock, chopped cloth or other filler to make molded articles, and by impregnating cotton cloth, nylon cloth or glass fiber products with this resin, laminates can be made that are resistant to shock and impact.

The following examples illustrate the invention:

Example 1 An ether'resin was made from resorcinol and the dichloride of hexaethylene glycol by reacting these materials in the following proportions:

The resorcinol and thedichloride of the hexaethylene glycol and 25 milliliters of water were weighed into a 500 milliliter 3neck,.round-bottomed flask equipped with a mechanical stirrer and reflux condenser. Some heat was applied and the flask flushed out with nitrogen. The sodium hydroxide was then dissolved in the rest of the water and this solution was added to the flask. The batch was heated up to the reflux temperature. The batch was stirred at reflux temperature until the titration of the alkali in a sample removed showed that the reaction had proceeded far enough to produce a resin of the desired molecular weight (about 600 to 3000) The batch was then neutralized with dilute 4 hydrochloric acid (27 milliliters of 5.9N HCl), about 5 milliliters additional acid was added and the batch was stirred thoroughly. The batch was transferred to a 1 liter flask, the water layer decanted and the batch washed with 4 portions of 400 milliliters each of boiling water. The

residual water was removed by heating in an oil bath finally at l40-145 C. under vacuum. The yield of resin was 152 grams. This resin had a molecular weight of 1000 as determined by the .camphor method.

Example 2 Five grams of the ether resin of Example 1 together with 5 grams of phenol-formaldehyde spirit-soluble laminating resin and 0.5 gram of hexamethylene tetramine were dissolved in 10 grams of acetone and alcohol (50-50 mixture) and the resulting solution was warmed slightly. Films were then cast on metal slides by floating about 1 milliliter of the solution on a slide and evaporating the solvent at temperatures ultimately reaching-70 to C. The resulting film was then baked at C. to C. for 15 minutes. This film was hard at baking temperature and at room temperature, substantially insoluble in ordinary organic solvents and would withstand considerable flexing without breaking. A film made of the phenol-formaldehyde resin alone was very brittle and would stand no flexing at all without cracking. 7

Example 3 Five grams of the ether resin of Example 1 was intermixed with 5 grams of phenol-formaldehyde resin (casting resin), 5 grams of acetone and 5 grams of ethyl alcohol,

The phenol-formaldehyde resin used was made by heating phenol (1- mol) with formaldehyde (2.5 mols) using sodium hydroxide as a catalyst. After reaction the batch was adjusted to substantial neutrality with lactic acid and then dehydrated under vacuum. As the resin was of the casting resin type and was, therefore, a heathardenable resin per se, it did not require the incorporation of additional aldehyde or catalyst but only heat to convert it to an insoluble thermoset resin.

Test slides were made by floating approximately 1 milliliter of the above solution onto flexible metal slides. The solvents were evaporated and then the slide was baked at 145 C. for 20 minutes. The resulting resin film was hard at baking temperature and at room temperature and was insoluble in ordinary solvents such as ketones and alcohol. The resin film was tough and not brittle and could be bent through an angle of 90 or more without breaking.

Example 4 The following materials were intermixed and the resulting solution was warmed.

Films were then east from this soi tion hy the method described in Example 2. The min was robbery and clear, demonstrating that the resins are oinpatible in this ratio.

Erafizple 5 The following materials were intermixed to form a solution as described in Example 2.

. c Grams Resin from nxampie 1 2 Phenol-formaldehyde sp'i'r sollible laminating I fesiii '(hat-haldiible per se) 8 Aeton'e 5 Ethyl albllol -n '5 The resulting film was insoluble in methyl ethyl lie'tdne and other common solvents. It was clear and definitely less brittle than a iilin made from phenol and formaldehyde alone.

Example 6 A solution was made from the following components:

Weight Mols v Grams Resoreinol 44 O. 4 Dichloride of tetraethylene glycol 94. 8 0.4 Sodium hydroxide (97%) l w 33 0. 8 Water n; -l- 116 The resin producedweighed 109 grams. It was a soft resin not soluble in water but soluble in solvents such asmethylethylketone. Its molecular weight was 1196.

When this 'ether'resin wasm-ixed with'an equal weight of a spirit soluble phenol-formaldehyde laminating resin plus hexamethyl'ene tetramine (5% of weight of ether resin) and a film made as described in Example 2, the resulting film was clear, showing that the two resins are compatible. The film was hard and not brittle as it could be bent through more than a 90 angle without breaking. Phenol and formaldehyde'jaloh'e 'in this same test will break :a-t the slightest bend'of the slide.

An other resin was made reacting resorc'inol with the dichloride time from nonaethylene glycol by replacing each of the two 'hydroxy groups with chlorine, in the manner'described "in Example 1, by reaetm thes'e'.fi1ateriels in the following proportiijnst Male Resorcinol 49. Bi #5 Dichloride of nonaethylene glycol 0. 45 Sodium hydroxide (97%). 0. Water 130.5

The ether resin produced was a soft resih, soluble in common organic solvents and had a molecular weight of 1665.

A film made from this ether resin {4 grams) plus spirit soluble phenol -formaldehyde resin (4 grams) and hexamethylene tetranune (0.2 gram), with acetone-ethyl alcohol as solvent, in a 'manner similar to Example L2. The resulting film was hard, insoluble and would withstand considerable flexing wlthelit breaking.

Example '9 An ether resin was made by reacting resorcinol with the dichloride made by replacing each of the two hydroxy groups in a polyethylene glycol of molecular weight of approximately 600:, in a manner similar to Example '1, exeept that chloroform was used to recover the ether resin from the reaction mixture.

This ether resin was a softresinof a molecular weight of 1623. It was compatible with heathardenable phenol-formaldehyde resins, and films made from such a combination in a menner similar to those previously described had properties similar to those of the resin of ample 2.

Example 10 An ether resin was made by reacting oreihol with the dichloride made by replacing each of the two hydroxy groups in hexaethylene glycol, m a manner similar to Example '1, by reactin these materials in the following proportions:

. want I the v Grams Resacetophenoue 48. 6 32 Dlchlor ev of polyethylene .glycol of molecular weight of 600 195.8 l 32 Sodium hydroxide (97%) Water S The ether resin produced was 'asoft resin weigh in; 206 rams. 'Wh'h mixed with a heat-hare- 7. enable phenol-formaldehyde resin in the manner described in Example 2 it was found to be compatible andto give aresin of greater flexibility and less brittleness than the phenol-formaldehyde resin alone.

. Example 12 An ether resin was made by reacting resorcinol with the dichloride made by replacing each of the two hydroxy groups in a polyethylene glycol of molecular weight of approximately 1000, in a manner similar to Example 1, by reacting these materials in the following proportions:

Weight Mols Grams ResorcinoL; 11.0 .10 Dichloride of poly hyienc glycol of molecular 94 8 m 314 12b 29.0

1 gran1s Hexamethylene tetr'amine do 0.5 Phenol-formaldehyde spirit-soluble laminating varnish (68% solids) do 14.7 Acetone milliliters 5 Ethyl alcohol"; do 5 These materials were dissolved in the solvents under slight warming. Then this solution was used toimpregnate strips of nylon cloth made from spun fiber. After the solvent had evaporated the strips were reweighed and there was 60% by weight of resin and 40% by weight of cloth in the dried strips. By pressing under heat a number of these coated strips, a laminate ap" proximately one-eighth inch thick was made. It was pressed at 140 C. to 145 C., and the pressure for thefirst two minutes was kept low, followed by eight minutes at 600 pounds per square inch. A strong, well-bonded laminate resulted which would withstand considerable flexing and was unaffected by immersion in a mixture of acetone and ethyl alcohol for an hour or more. The tensile strength was. determined on a sample of this type of laminate and it was found to be 12,200 pounds per square inch. There was considerable elongation of the test sample. before breaking which further proves that this resin is not brittle like ordinary phenol-formaldehyde.

' A resorcinol ether-resin was made from resorcinol and the dibromide of hexaethylene glycol by reacting the following materials in the follevie rrepcr ion a The'sodium hydroxide, water and methyl alcohol were charged into a 500 ml. round bottom flask equipped with a reflux condenser and mechanical stirrer. The flask was flushed out with nitrogen, then the resorcinol was added and some heat applied while the dibromide was dropped in with stirring over about 10 or 15 minutes. The batch was heated to the reflux temperature (about 74 C.) and held there while being stirred until the titration of a test sample showed that the reaction was about to complete. About 4 hours were required to reach this stage. The batch was then neutralized with 4.5 ml. of 6N hydrochloric acid, washed with several portions of hot water, and then dehydrated as described in Example 1.' The product weighed 72 grams. It was a clear, amber-colored, soft resin which barely flowed at room temperature. The molecular weight of this resin was 1330, by the camphor method.

5 grams of this ether-resin and 5 grams of an acid-catalyzed, molding-type of phenol-formaldehyde resin and .7 gram of hexamethylene.

tetramine were dissolved in 10 ml. of ethyl alcoholeacetone solvent (50-50 mixture). About 1 milliliter of this solution was floated onto a sheetmetal slide, the solvent evoporated, and the resulting film baked for 15 minutes at C. The resin film was now clear, hard and had considerable flexibility.

It has also been found in accordance with the present invention that in the preparation of ether-resins by the use of dihalides which react rather rapidly, the reaction can be controlled more readily if part of the water is replaced by an organic solvent such as one of the low aliphatic alcohols, and a lower reaction temperature is used. With either the dichlorides or dibromides, if the reaction is allowed to proceed too far, an insoluble resin may result.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above methods and products without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A substantially insoluble heat-hardened resin comprising the product of reaction under heat and in the. presence of a substance selected from the group consisting of formaldehyde and a formaldehyde-yielding substance of from approximately 10 parts to approximately 90 parts by weight of a heat-hardenable phenol-formaldehyde composition from approximately 90 parts to approximately 10 parts by weight of an ether resin having the formula:

in-which n is an integer-not less than 4 and not greater than approximately 30, m is an integer from approximately-2 to 10, X is a halogen selected from the group consisting of chlorine and bromine, and R. is selected from the group consisting of lower alkyl and acyl radicals and hydrogen.

2. A substantially insoluble heat-hardened resin comprising the product of reaction under heat of from approximately 10 parts to approxi- 9" mately 90 parts .by weight of a thermosetting resin made with phenol, and formaldehyde in the approximate ratio of l;2 .5 respectively and from approximately 90 parts to approximately parts by weight of an ether resin having the formula:

in wh h n s an. in r not less. nane a d. no reater than app mately 3. m is an. int e from approximately .2. to 10,v i a halog memorial-m oomoxorx in which n is an integer, not less than 4 and not greater than approximately 30, m is an integer from approximately 2 to 10, X is a halogen se lected from the group consisting of chlorine and b m ne, and R1 se ecte r m't e o p co st of lower alkyl and. acyl ra i s and hydrogen, together with from approximately 1 to 10 parts by weight of a substance selected from the group consisting of Iormaldehyde and formaldehyde-yielding substances for each 100 parts of the total of the phenolformaldehyde and ether resins.

4. A substantially insoluble heat-hardened resin comprising the product of reaction under heat and in the presence of an alkaline catalyst of from approximately 10 parts to approximately 90 parts by weight of an A-stage soluble phenolformaldehyde resin and from approximately 90 parts to approximately 10 parts by weight of an ether resin having the formula:

' (oonzoni)wo Jewel-1720112)): p4 I in which n is an integer not less than i and not greater than approximately 30, m is an integer from approximately 2 to 10, X is a halogen selected fromthe group consisting of chlorine and bromine, and. R is selected from the group consisting of lower alkyl and 'acyl'radicals and hydrogen, together with from approximately 1 to 10 parts by weight of a substance selected from the group consisting of formaldehyde and formaldehyde-yielding substances for each 100 parts of the total of the phenol-formaldehyde and ether resins. t

5. A substantially insoluble heat-hardened resin comprising the product of reaction under heat and in the presence of an alkaline catalyst of from approximately 10 parts to approximately :90 parts by weight of an A-stage soluble phenolformaldehyde resin and from approximately 90 parts to approximately 10 parts by weight of an ether resin haying the formula;

in which n is an integer-not less than 4 and not greater than approximately 30, m is an integer from app o mate y to 1 0 .X is a ha lected from the group cfinsistingof chlorine and bromine, and R is selected from the group consisting of lower alkyl and acyl radicals and ,hy-

drogen, together with from approximately 1 to 10 parts by weight of hexamethylene tetramine for each parts, of the total of the phenol-formaldehyde and ether resins.

6. A substantially insoluble heat-hardened resin comprising the product of reaction under heat and in the presence oi a substance selected from. the group consisting of formaldehyde and a formaldehyde-yieldin substance of from ape proximately 10 parts to approximately 90 parts by weight of a heat-.hardenable phenol-iormaldehyde composition and from approximately $0 parts to approximately loparts by weight ofan ether resin which comprises the product of'reaction under heat. and alkaline conditions of a dihydric phenol having the formula:

in which R is selected fromthe group consisting of lower alkyl and acyl radicals and hy.-. drogen, and a polyethylene'glycol dihalide having the formula:

in which X is a halogen selected from the group consisting of chlorine and bromine, and n is an integer not less than approximately 3 nor more than approximately 30.

-7. The method of forming substantially insolue ble heat-hardened resins comprising reacting in the presence of a substance selectedfrom the group consisting of formaldehyde and a formaldehyde-yielding substance from approximately 10 parts to approximately 90 parts by weight of a heat-hardenable.phenol formaldehy e c mp sition with from approximately 90 parts to approximately 10 parts by weight of an ether rosin having the formula:

(0 32) n O o omcapwx in which. is an integ r not less than. 4: and not greater than approximately 30,, m is anintegor from approximately 2 to 10, X is a halogen selected from the group consisting of chlorine and bromine, and R is selected irom the group consisting of lower alkyl and acyl radicals andhydrogen. l

8. The method of iorming substantially insolu-e ble heat-hardened resins comprising reacting in the presence of a substance selected from the group consisting of formaldehyde and a formaldehyde-yielding substance under heat from approximately 10 parts to approximately 90 parts by weight of a heat-hardenable phenolformaldehyde composition with from approximately 90 parts to approximately 10 parts by weight of an 11 ether resin which comprises the product of reaction of a dihydric phenol having the formula:

HO OH in which R is selected from the group consisting of lower alkyl and acyl radicals and hydrogen, and a polyethylene glycol dihalide having the formula:

in which X is a halogen selected from the group consisting of chlorine and bromine, and n is an integer not less than 3 nor more than approximately 30, the molecular weight of such ether resin being between approximately 600 and 3000.

wcrncmh-o- 1 L R J in which n is an integer not less than 4 and not greater than approximately 30, m is an integer from approximately 2 to 10, X is a halogen selected from the group consisting of chlorine and bromine, and R is selected from the group consisting of lower alkyl and acyl radicals and hydrogen.

10. The method of forming substantially insoluble heat-hardened resins comprising reacting in the presence of a catalyst from approximately 10 parts to 90 parts by weight of an A-stage soluble phenol-formaldehyde resin with from approximately 90 parts to approximately 10 parts oomom). 1 i R l by weight of an ether resin having the formula: in which n is an integer not less than 4 and not greater than approximately 30, m is an integer from approximately 2 to 10, X is a halogen selected from the group consisting of chlorine and bromine, and R is selected from the group consisting of lower alkyl and acyl radicals and hydrogen, together with from approximately 1 part to parts by weight of a substance selected from the group consisting of formaldehyde and formaldehyde-yielding substances for each 100 parts of the total of the phenol-formaldehyde and ether resins.

11. The method of forming substantially insoluble heat-hardened resins comprising reacting in the presence of an alkaline catalyst approximately equimolecular proportions of an A-stage soluble phenol-formaldehyde resin with an ether resin having the formula:

(O CHaCHr)-X no o cmom)r.-o (comment-x i/i R J m in which n is an integer not less than 4 and not greater than approximately 30, m is an integer from approximately 2 to 10, X is a halogen selected from the group consisting of chlorine and bromine, and R is selected from the group consisting of lower alkyl and acyl radicals and hydrogen, together with from approximately 1 part to 10 parts by weight of hexamethylene tetramine for each 100 parts of the total of the phenolformaldehyde and ether resins.

12. The method of forming substantially insoluble heat-hardened resins comprising reacting in the presence of an alkaline catalyst approximately equimolecular proportions of a thermosetting resin made with phenol and formaldehyde R L R l V m in which n is an integer not less than 4 and not greater than approximately 30, m is an integer from approximately 2 to 10, X is a halogen selected from the group consisting of chlorine and bromine, and R is selected from the group consisting of lower alkyl and acyl radicals and hydrogen.

13. A laminated article which comprises a fiber base and a substantially insoluble heat-hardened resin comprising the product of reaction under heat and in the presence of a substance selected from the group consisting of formaldehyde and a formaldehyde-yielding substance of from approximately 10 parts to approximately parts by weight of a heat-hardenable phenol-formaldehyde composition and from approximately 90 parts to approximately 10 parts by weight of an ether resin having the formula:

GEORGE L. DOELLING. KENNETH H. ADAMS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,060,715 Arvin Nov. 10, 1936 2,485,711 Doelling et al Oct. 25, 1949 

1. A SUBSTANTIALLY INSOLUBLE HEAT-HARDENED RESIN COMPRISING THE PRODUCT OF REACTION UNDER HEAT AND IN THE PRESENCE OF A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF FORMALDEHYDE AND A FORMALDEHYDE-YIELDING SUBSTANCE OF FROM APPROXIMATELY 10 PARTS TO APPROXIMATELY 90 PARTS BY WEIGHT OF A HEAT-HARDENABLE PHENOL-FORMALDEHYDE COMPOSITION FROM APPROXIMATELY 90 PARTS TO APPROXIMATELY 10 PARTS BY WEIGHT OF AN ETHER RESIN HAVING THE FORMULA: 